Restore the handling of the --arch argument passed to the Driver that was inadvertently
removed in r214319.

<rdar://problem/17948431>


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@215165 91177308-0d34-0410-b5e6-96231b3b80d8
Revert "Fix the build broken as a result of deleting jit from LLVM."

jit was re-added back to LLVM, so now we require to link against it
again.  Should it get removed again, then revert this revert.

git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@215170 91177308-0d34-0410-b5e6-96231b3b80d8
Disable the command pipe in ConnectionFileDescriptor for Windows.

The select() API on Windows is not compatible with objects other
than sockets, so passing a descriptor for the command pipe to this
function is guaranteed to fail.  ConnectionFileDescriptor is still
broken on Windows after this patch, but slightly less broken than
before.

git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@215172 91177308-0d34-0410-b5e6-96231b3b80d8